Infusion devices and systems have become relatively prevalent in the medical field for use in delivering or dispensing prescribed medication such as insulin to a patient. In one form, such devices comprise a transportable, pocket-size pump housing capable of receiving a reservoir of medication for administration to the patient through an associated catheter or infusion set.
Infusion devices have significant advantages over traditional medication delivery methods because of their precision, consistency, and versatility. Patients are able to set exact dosage amounts and generally benefit from receiving medication from pumps during physical activity or other occasions that would otherwise not easily be suited for doing so. As a result, infusion pumps have effectively reduced the restrictions that a diabetic patient's medical needs place upon him allowing the patient to live a more active and fulfilling lifestyle.
Generally, medication reservoirs have been used with the infusion devices to deliver medication to the patient. Typically, the medication reservoir is operatively inserted in, or attached to, the infusion device. A plunger is then actuated to force medication out of the reservoir, and deliver the medication via a tube to an insertion site on the patient.
Prior to methods being developed for detecting the presence or identifying the contents of a medication reservoir, a user manually checked if the reservoir was attached or inserted into a delivery device. The user was also responsible for ensuring that the medication or dosage was the correct one to administer. These steps are critical because a lack of the reservoir in the infusion device prevents the patient from receiving vital medication. Moreover, administration of an incorrect medication or dosage can lead to patient injury or death. Generally, the user must know what type of medication is being administered because there are often different dosing requirements for different concentrations of the same medication.
To overcome the drawbacks concerning what type of medication is contained in the reservoir, information related to the medication was printed on the exterior of the reservoir. However, this method suffers because the user must still view the printing on the reservoir and understand the information presented.
Other systems for providing information about the reservoir to the delivery device have been developed but also suffer from various disadvantages. For example, a delivery system includes mechanical switches that are manipulated by the reservoir when the reservoir is inserted into the device to provide information about the reservoir. However, such a device is disadvantageous because inclusion of the mechanical switches undesirably increases the size of the delivery device. Moreover, the switches must be accessible to the reservoir, and thus, it is difficult to maintain a waterproof device housing to protect the internal components of the delivery device from any fluids escaping from the reservoir or otherwise entering the device. The system is also susceptible to error when the reservoir's orientation in the device is not in an ideal position with respect to the switches.
In yet another example, a medication delivery system includes a bar code reader mounted in the delivery device. The bar code reader is used in conjunction with a medication reservoir having a bar code on its surface. The bar code provides information related to the medication contained in the reservoir, such as type, volume, dosage, etc. Accordingly, when the reservoir is inserted into the delivery device, the bar code reader in the device reads the bar code on the reservoir, and uses the information obtained from the bar code to operate the device, or provide the information to the user on a device display.
However, such a system suffers from several drawbacks. For example, bar code readers need to be a certain distance away from the bar code to properly read the bar code. Consequently, devices accommodating bar code readers are larger in size, which is undesirable to users. Moreover, the bar codes on the reservoir require precise positioning in the device to be properly read by the bar code reader. Hence, device reliability and accuracy are easily lowered if the reservoir is moved slightly away from its ideal position in the device.